UNIT I: FOREST AND TUNDRA ECOLOGY UNIT 1. FOREST AND TUNDRA ECOLOGY National Wildlife Refuge System 1011 E. Tudor Road Anchorage, Alaska 99503 http://alaska.fws.gov/fire/role/ Role of Fire 2007 UNIT I 5 UNIT I: FOREST AND TUNDRA ECOLOGY An Overview Reading the Alaskan Environment (K-12) In an outdoor activity, students closely observe their environment. Identifying Objects (3-8) Students learn about dichotomous keys and how they are used to identify plants. Critter Search (K-12) Students look for evidence of small animals and their tracks in an outdoor setting. The Summer Plant Keys (6-12) Student use a game format to construct a dichotomous key representing the summer plants of the boreal forest. Blind Walk (K-12) In an outdoor activity, students explore the local ecosystem using only their sense of touch and smell. Transect Study (6-12) Students set up transects near the school to systematically study the local ecosystem. Making the Forest and Tundra Wildlife Connection (5-12) Students participate in an active game to form food chains of the boreal forest. The Succession Race (5-8) Students play an active game in which they pretend they are plants. As the plants progress through boreal forest succession they encounter conditions which affect them. Boreal Forest Succession (5-8) Students observe and record the different stages of forest succession around their school grounds, and illustrate succession in the boreal forest by making field notebooks and a mural. Living on the Edge (5-8) Students play a game to create a vegetation mosaic and discuss their influence on wildlife diversity. AND ADAPTED AND/OR REPRINTED FROM ALASKA’S FORESTS AND WILDLIFE (from the Alaska Wildlife Curriculum): Tree Leaf Relay (3 – 12) Students learn the identifying characteristics and names of several Alaska tree species by examining leaves, and participating in a relay race. Tree History – Your History (K – 12) Students learn dendrochronology techniques to determine the age of trees and the dates that trees died or were logged, as well as the dates of important forest events. Role of Fire 2007 UNIT I 6 Role of Fire UNIT I: FOREST AND TUNDRA ECOLOGY BACKGROUND Central and western Alaska is dominated by WHAT IS THE TUNDRA? two major ecosystems, the boreal forest and Tundra is an environment characterized the tundra. Although these ecosystems mainly by the absence of trees. At first look very different, they are similar in many glance, tundra appears monotonously the ways. same. But closer examination reveals that, like the boreal forest, the tundra is a mosaic. WHAT IS THE BOREAL FOREST? It is a mosaic of wet, sedge-grass The boreal forest is the largest and northern meadows, thickets of low shrubs, and dry most forest ecosystem in the world. The areas vegetated by cushion and mat- boreal forest is the predominant ecosystem forming plants. in interior Alaska. Viewed from the air, this forest looks like a giant patchwork quilt or Tundra occurs predominantly at higher mosaic. Large patches of scraggly black elevations and in the western and northern spruce trees on poorly drained and areas of Alaska (Fig. 1). However, the permafrost soils, contrast with hillsides of boreal forest and tundra frequently occur light green birch, aspen and tall white together. Patches of tundra are often found spruce. within the boreal forest areas, and patches of forest can be found in tundra areas. Role of Fire 2007 UNIT I 7 WHAT ARE THE NONLIVING the horizon. The winter sun delivers little COMPONENTS OF BOREAL FOREST heat and light to the forest and tundra, and AND TUNDRA? more heat is lost to the atmosphere than is Like all land ecosystems, Alaska boreal received from sunlight. Winter air forest and tundra include the nonliving temperatures plunge below zero, often components of air, water, soil, and energy reaching extremes of -40o F (-40o C) or (in the form of sunlight). These form the colder. physical surroundings of the ecosystem. Some physical features of the boreal forest During summer when the earth's northern and tundra are: latitudes are tilted towards the sun, day length is nearly 24 hours and the sun rises 1. strong seasonal patterns (severe higher above the horizon and delivers more winters and short, warm summers) light and heat per hour. The boreal forest 2. permafrost and tundra then receive more heat in 3. little precipitation sunlight than they lose. Thus, temperatures 4. lightning-caused fires rise. Air temperature extremes above 90o F 5. ice jams and floods (32.2o C) regularly occur in the boreal forest. In the tundra, summer temperatures are Seasonal Patterns usually cooler, but may still reach extremes In winter, when the northern regions are of 68o F (20o C). tilted away from the sun, the land receives only a few hours of light each day. During Permafrost these few hours, the sun barely rises above Despite the warmth of summer, the climates of both the boreal forest and tundra are dominated by the severe cold of winter. Role of Fire 2007 UNIT I 8 Thus, permafrost, or permanently frozen everywhere. In other areas of the state, ground, occurs in some areas. Surface permafrost is discontinuous, occurring only soils called the active layer thaw out each in some places but not everywhere. Where summer and refreeze in winter. Beneath permafrost is discontinuous, it generally the active layer, permafrost remains frozen underlies north-facing hillsides and poorly year-round. drained lowlands. Permafrost is absent from most south-facing hillsides and from Permafrost underlies most tundra areas and the well-drained sandy soils around large occurs throughout the northern portions of bodies of water. In the southernmost the boreal forest. In these northern areas, reaches of the boreal forest, permafrost is permafrost is continuous, occurring sporadic or absent (Fig. 2). Precipitation Fire The boreal forest and tundra receive little Wildland fires caused by lightning are a precipitation; in both ecosystems the natural part of Alaska's boreal forest and average annual precipitation is only 5 to 12 tundra ecosystems. Layers of charcoal in inches (120-300 mm). This is similar to the lake beds, wetlands, fire-scarred trees, and amount of precipitation in many deserts of logs provide evidence that fires have the world. However, unlike a desert, many occurred in the boreal forest environment sites in the tundra and boreal forest are for thousands of years. Due to the absence moist or wet. of trees, tundra fires leave little long-lasting evidence of their passage. Therefore, the Moist and wet conditions occur despite low history of fire in tundra regions is less clear. precipitation partly because cool Based on historical fire records, scientists temperatures cause low evaporation rates. think fires naturally occur in some tundra In addition, water cannot seep into regions, such as the Seward Peninsula, but permafrost soils. are rare or absent from other tundra areas. In general, fires occur less frequently and Role of Fire 2007 UNIT I 9 burn smaller areas in tundra than in the Ice Jams and Flooding boreal forest. However, large tundra fires During spring thaw, ice quickly breaks up on have been recorded. Fire is one of the the rivers of Alaska. The ice pushes it’s greatest forces of change in the boreal way downstream, scouring the banks and forest and tundra. often leaving tree and plant roots exposed. This ice can also pile into ice jams which may dam the river and cause extensive flooding. WHAT ARE THE LIVING COMPONENTS OF THE BOREAL FOREST AND TUNDRA? Many kinds of living things inhabit the boreal down or decay dead plants and animals. forest and tundra, including microscopic Other fungi live together with certain kinds organisms, fungi, plants, and a wide variety of algae and are called lichens. Lichens, of animals (insects and other invertebrates, like plants, photosynthesize (they convert birds, and mammals). air, water, and sunlight into sugars for food). Microscopic Organisms Lichens are a dominant organism in some The microscopic organisms of the boreal tundra regions and an important nutrient forest and tundra include bacteria, algae, source for caribou. and protozoa. These creatures are easy to overlook since a microscope is needed to Plants observe them. But, they are important parts Plants are the most noticeable of the living of the forest and tundra. They live in the components of both the boreal forest and soil, water, and air and inside other living tundra. The dominant species of trees of things. the boreal forest include black and white spruce, birch, aspen, and balsam poplar. A Fungi and Lichens variety of shrubs, herbs, grasses, mosses, Fungi of the boreal forest and tundra and ferns grow in association with these include mushrooms, molds, rusts, mildews, trees. The boreal forest is often classified and rots. Most are important into several forest cover types based on the decomposers, meaning they help break dominant species of trees and associated plants. Role of Fire 2007 UNIT I 10 Tundra areas are predominately treeless, Common tundra species include moose, but the dominant tundra plants vary from caribou, voles, lemmings, arctic ground area to area. Mosses and sedges are the squirrels, red fox and arctic fox, wolves, most abundant plants in wet tundra. In wolverines, and brown bears. moist sites, dryas, dwarf shrubs such as willow, bog birch, crowberry, and Labrador tea are important. Mat and cushion plants such as moss campion and arctic bearberry grow in dry tundra. Animals The animals of the boreal forest and tundra include birds, mammals, amphibians, and insects and other invertebrates. See the Alaska Ecology Cards for a detailed listing. Birds Birds of the boreal forest and tundra of Alaska include residents (birds that live here year-round) and migrants (birds that nest Did you know that voles are some of the here but winter elsewhere).